Toothbrush



FIG. 1 is a perspective view of a toothbrush, showing my new design;

FIG. 2 is a front view thereof;

FIG. 3 is a left end view thereof;

FIG. 4 is a right end view thereof;

FIG. 5 is a top plan view thereof; and

FIG. 6 is a bottom plan view thereof. 

The ornamental design for a toothbrush, as shown. 